A storage server is a special-purpose processing system used to store and retrieve data on behalf of one or more client processing systems (“clients”). A file server is an example of a storage server. A file server operates on behalf of one or more clients to store and manage shared files in a set of mass storage devices, such as magnetic or optical storage based disks or tapes. The mass storage devices may be organized into one or more groups of Redundant Array of Inexpensive Disks (RAID). In a storage area network (SAN), a storage server can provide clients with block-level access to stored data, rather than file-level access. Some storage servers are capable of providing clients with both file-level access and block-level access, such as certain filers produced by Network Appliance, Inc. of Sunnyvale, Calif.
In certain circumstances, a storage server may require replacement. The reasons for replacement may include failure or other operational problems, necessary maintenance, or installation of an upgrade. However, the operations of the server may require continuation during the replacement of the server.
In conventional operations in a session-based environment, sessions will terminate in a transfer to another server because the session information isn't propagated to or available for the replacement server. Further, the replacement of one server with another may result in an interruption in service if the change does not occur quickly enough. In such an environment, a communication from a client may be made during a replacement process. If there is a sufficient delay in a response to the communication, this delay may cause the session to be terminated.